My experience with aluminium welding stopped at 4mm thick sheets while thicker ones were easy to weld, I never managed to weld thinner ones. Most repairs need to remove aircraft structure for access, and a riveted structure is easier to disassemble and to put together again after the repair using slightly thicker rivets. You need an AC TIG welder to disrupt the aluminium oxide layer, so your choice of welding techniques is rather limited.Īlso, riveted structures are easier to inspect and to repair. To harden the finished structure again is rather impractical in most cases, so riveting is the better alternative.Ī third speciality is the oxide layer on aluminium, which has a higher melting temperature than the base material. If they are heated and rapidly cooled by welding, the copper distribution would be changed and the material would be weakened around the welding area. The usual alloys use copper atoms dispersed through the aluminium matrix which locally distort the atomic lattice and strengthen it. High-strength aluminium is produced by progressively aging and precipitation hardening the material. Also, the melting temperature of steel and titanium is high enough for it to glow long before it melts, while aluminium will melt without giving you any optical hint of its temperature. For very thin sheets, special equipment like a water-cooled copper backing on which the aluminium sheets rest, so their back is cooled, are needed. While welding thin sheets of steel is trivial, it needs lots of experience in aluminium. Also, heat conductivity in iron-based alloys is lower than in aluminium, so heating steel locally will keep the surrounding material cooler and more solid compared to aluminium.

While steel has a temperature range in which it gets more and more runny, aluminium alloys change from solid to liquid within a few degrees. Aluminium is such a fine material for aircraft structures that the need to rivet it is gladly accepted. Short answer: High-strength aluminium alloys are tricky to weld correctly.

Riveted vs welded jon boat